Nut-tapping machine.



No. 768,503. PATENTED AUG. 23, 1904.'

G. F. ZWILLING & C. W. RICHARDS.

NUT TAPPING MACHINE.

APPLICATION FILED JUNE 12, 1903.

8 SEEE HEETI.

WTNESSES.'

No. 768,503. PATENTBD AUG. 23, 1904.

` G. F. ZWILLING & C. W. RICHARDS.

`NUT TAPPING MACHINE.

APPLIOATION FILED JUNE 12, 1903.

' No. 768,503. PATENTED AUG. 23, 1904.. G. F. ZWILLING & G. W. RICHARDS.

NUT TAPPING MACHINE. APPLIQATIoN FILED JUNE 12,1903. No MODEL. sSHEETS-SHEET a.

lllllllllllllllllllll llllllllll'j'l l l' Mmmm UNH s@ Ilm f y mmm lPATENTED AUG. z3, 1904..` G. P. ZWILLING at o. w. RICHARDS.

NUT TAPPING MACHNE.

y No. 768,503. PATBNTED AUG. 2a, 1904. G. F. ZWILLING A c. w. RICHARDS.NUT TAPPING MACHINE.

kAPPLICATION FILED JUN- 12,1903.

No MODEL.

8 SHEETS-SHEET 5.

W/TNESSES.' v/N VENTO/i3 No'. 768,503. PATBNTED AUGfz'a, 1904. G. P.ZWILLING &'c. W. RICHARDS. NUT TAPPlNG MACHINE.

APILICATLN FILED JUNE 12, 1903.

N0 MODEL. 8 SHEETS-SHEET 6.

NVENTOff No. 768,503. l I PATBNTED AUG. 23, 1904, G. P. ZWILLING & C. W.RICHARDS.

NUT TAPJPING MACHINE. APPLIoAToN FILED JUNE 12,1903.

. No MODEL. s SHEETS-SHEET 7.

4PATENTED AUG. 23, 1904. G. F. ZWILLING al c. W. RICHARDS.

NUT TAPPING MACHINE.

APPLICATION FILED JUNE 12,1903.

a sums-8111121' s.

NO MODEL.

UNirnDl STATES Patented August 23,1904.

V PATENT OFFICE.

OHIO, ASSIGNORS TO. ACME MACHINERY COMPANY, OF CLEVE- LAND, OHIO.

NUT-TAPPING MACHINE.

SPECIFICATION forming part of Letters lPatent No. 768,503, dated August23, 1904. Application filed JunelZ, 1903. Serial No. 161,181 (No model.)

To all whom, t may concern:

Be it known thatwe. GEORGEF. ZwiLLIvc.l

and CHARLES W. RICHARDS, citizens of the United States, and residents ofCleveland, in the county of Cuyahoga and State of Ohio, have invented anew and Improved Nut-Tapping Machine, of which the following is a full,

clear, and exact description.

This invention relates to a machine-for automatically threading nuts;and the prime object of the invention is to produce a machine,

in which the tapping operations are practically continuous, thus greatlyincreasing the speed of the machine. I

This specification is anexact description of one example of ourinvention, while the claims deline the actual scope thereof.

The organized machine as here illustrated may be outlined as follows: Onthe frame of the machine are mounted two shafts having means forrevolving and simultaneously reciprocating them, these means including'devices for automatically'reversing the d1rection ofrevolution. At eachend of each shaft is arranged a peculiar chuck and relief device,

the chucks carrying thetaps and the reliefv devices permitting the partsto give should the taps encounter extraordinary obstacles. Moving withsaid shafts are peculiarly-constructecl ejectors, which displace thefinished products, and driven in time with the devices' for driving thesaid shafts are the feedingslides, which deliver the blank nuts to fourchutes arranged over the respective taps. The shafts carrying the tapsare reciprocated simultaneously toward and fromthe respective ends ofthe machine, and' therefore two taps are always at work at one end whilethe other taps at the opposite end arein the act of unscrewing from thefinished nuts. The taps act continuously, therefore, to screw into andunscrew from the blanks, and the feeding devices supply the blanks tothe taps vas fast as the blanks can be operated upon. This produces acontinuously-operating and exceedthe line 6 6 in Fig. 1.

drawings, forming a part of this specification,

in which similar characters of reference indicate corresponding. partsin all the views.`

Figure 1 is a plan view of the machine. Fig. 2 is a side elevationthereof. Fig. 3 is a longitudinal section on the line 3 3 of Fig. 1.Fig. 4 is a longitudinal section on the line 4 4 of Figfl. Fig. 5 is anend elevation showing particularly the chutes through which the blanksare fed. Fig. 6 is a cross-section on Fig. 7 is an enlarged detail viewshowing the relation of the taps to theblanks prior to the engagementbetween' the two.y Fig. 8 is a similar View showing the tap engaged withthe appropriate blank. Fig. 9 is a detail plan view of the ejectorSuited both to square and hexagonal nuts. Fig. 10 is an enlarged frontview of the ejector with the parts adjacent thereto and showing theejector operating in connection with the hexagonal nuts. 'Fig 11 is aplan view of a modiiicationof the lead-screw. Fig. 12 is a section onthe line 12 12 of Fig. 11, and Fig.

13 is a sectional elevation on the line 13 13 of I "Fig. 1l.

The base 15 of the machine carries pedestals 16 and 17, (see Fig. 3,-)and in these pedleys 19 and 20 thereon and a single doublefaced fixedpulley 21 located between the pulleys 19 and 20. Reversely-movingdriving-belts are adapted to operate with these pulleys, (see Fig. 6,)and said belts are engaged 'by guides 22, carried on arms 23, fastenedby clamps 24 to-a shipper-shaft 25,

'which is mounted to slide longitudinally in extensions 16 and 17 of thepedestals 16 and 17. One end of the shipper-'shaft 25, outside of thebearings thereof, is provided with a downwardly-extending arm 26, whichcoacts with the devices for operating the shaft 25, as will behereinafter fully set forth. `The belt-holders 22 are so arranged'thatupon the reciprocal movement of the shaft 25 one of the belts is thrownonto the fast pulley 21, the other belt being simultaneously thrown onto29 turns one of said arms 31 engages the arm .Sol

. tudinal slots43, formed in the sleeve 39. The

26 and throws the shaft 25 in one direction, thus reversing thedirection of movement of the shafts 18 and 29. These elements continueto turn in the reverse direction until the other arm 31 strikes theopposite side of thearm 26, and the shaft 25 is thrown back ,to itsfirst position, whereupon the direction of revolution is again reversed.

Fastened to the shaft 29 alongside of the worm 27 is a pinion 32, whichis in mesh with a toothed sector 33, formed on a lever 34, mounted torock around the intermediate fulcrum, (indicated at 35,) said fulerumconsist ing of a pin mounted between the before-men tioned pedestals 30.The lever 34 projects downward below the table of the machine and hasits lower end slotted to receive a slide 36, which is adjustablelongitudinally of the lever by means of a screw 37. To this slide ispivoted a link 38, and it is clear that by adjusting the slide 3G thethrow of the lever of the link 38 may be regulated at will. The link 38is formed in two sections, and these sections are joined by a yieldingor relief connection, which is set to break when a certain strain isreached and which comprises a sleeve 39 on one section of the link, saidsleeve having eXteriorly-located springs 40 attached thereto, and'thesesprings carrying pins 41, which project through the sleeve and havebeveled inner ends engaged in correspondinglyformed cavities in theother section of the link, said other section of the link fittingslidably within the sleeve 39 and having a transverse pin 42 fastenedthereto and loosely fitted at its ends in longiengagement of the pins 41with the inner linksection is sufiicient to hold the two sections of thelink rigidly engaged under all conditions of operation. However, shouldthe load on the link become abnormal (whichin practice might be due tothe clogging of the machine) the pins 41 will be caused to jump out ofthe cavities in the inner link-section, and then the two sections of thelink will slide the one on the other, and no movement will betransmitted beyond that section which is directly connected with theslide 36. Said link 38 is connected to a rod 44, which lies under thetable of the machine and has its ends pivoted, respectively, toelbow-levers 45, said levers being suitably fulcrumed just above thetable of the machine and working through cavities in the table. (SeeFig. 3.) The upper ends of the elbow-levers 45 are connected by links 46with the feeding-slides 47, said slides being of inverted-V shape (seethe dotted lilies in Fig. and moving vertically in suitable guides 48,formed in the blank-hoppers 42). The limbs of the slides 47 arerespectively adjacent to the feed-chutes to guide the blanks thereinto.Said hoppers 49 are two in number, located one at each end of themachine, and from each side of each hopper outwardly and downwardlyextending blank-chutes 50 project. As the feed-slides 47 move downwardin the guides 48 a number of nuts are engaged with the slides, and thenas the slides move upward said blanks are rolled oi'i at each side intothe respective chutes 50, when the slides 47 reach a height suiiicientto put the lower sides of the slides into positions opposite the mouthsof the chutes 50. It will be observed that should any of the blanks clogin the hoppers, and thus prevent the proper action of the slides 47, theconnection between the sections of the'link 38 will collapse, andbreakage of the machine is thereby prevented. As the link 38 movesbackward or returns the pins 41 will rengage the cavi ties in the innerliiilvsectioii, and then the link will operate normally unless, however,the same or a second obstruction is met with, whereupon the connectionwill again collapse, as described. As the blanks fall through the chutes50 they pass into position for engagement by the taps, and the mechanismfor mounting and operating these parts of the machine will now bedescribed.

Returning to the shaft 18, said shaft carries a pinion 51, which mesheswith and drives an intermediate gear 52, rotatable on a stud 53, carriedby the pedestals 16 just below the shaft 18. rlhe gear 52 (see Fig. 6)is intermediate to two gears 53, with which latter gears said gear 52meshes. '.lhese gears 53 being located at the respective sides of themachine are mounted to turn loosely on bushings 54, (see Fig. 4,) heldfast in suitable bearings 55, sustained on thel table of the machine.Passing loosely through the bushings 54 and disposed in parallelismlongitudinally of the machine are two shafts 56, which are held in thesaid bushings to slide and to turn and which are provided withfeed-screws 57,

i fastened to the shaft and working in stationary nuts 58, these nuts 58being mounted on the table of the machine, as illustrated. ltotarymovement imparted to the shafts .56 by mechanism which will behereinafter described will result in a simultaneous longitudinalmovement of said shafts, owing to the action of the parts 57 and 58, andit is clear that upon a reversal of this rotary movement theA vprojecttransversely through the sleeves .61'

and are formed with beveled ends engaging corresponding cavities in theshafts 56. By these means connections are effected between the ends ofthe shafts 56 and the sleeves 61, said connections being rigid underlnormal conditions and breaking to permit independent movement of theparts under abnormal strains. To the sleeve 61, which is adjacent to thegear 53, a disk 64 is fastened, and said disk is formed withtwo or moreopenings therein, throughl which pass loosely studs 65, fastened to thegear. 53. By

these means and by means of the pins 59, iitting in the slots 60r of thesleeves 61, the rotative movements of the gears 53 are communicated totheir respective shafts 56. sleeves 61 are mount- The outer ends of theed loosely the table said boxes atathe outer vextremities of thesleevesare located the chucks for fastening in place the taps 67. Saidchucks comprise collars 68, encirclingthe sleeves 61 and provided withscrews 69 for holding the collars in place and also for holding withinthe in suitable boxes 66, sustained on sleeves the thimbles 70,y whichencircle the shanks of the taps.

Said collars 68 also carry screws 71, which pass through openings in thesleeves y61 and in the dicates keys which are passedtransversely throughthe sleeves 61 and thimbles 70 to hold alternately moved into andretracted from the:

work, two taps being always active and two taps bemg always unscrewingfrom the iinished nut.

Mounted on the table directly below the outer end of each sleeve 61 is aslide 73, these slides having upward extensions 7 3, through which theouter ends of .thesleeves .6.1, pass loosely, and between saidextensions 73L and the boxes 66 expansive spiral springs .74 operate.Said springs tendto throwtheslides outward, causing them to follow theoutward lmovement of the adjacent collars 68, and as said. collars moveinward the slides 73 are drop. the end portions of of the machine, andoutward fromy thimbles and diy rectly engage the shanks of the taps. 7 2inforced to follow and the springs 74 are compressed. vAttached to eachslide 73 isan ejector 7 5, said ejectors being in the form oflhorizontally-disposed plates projected outward from the, slides andcapable of passing through the lower extensions 50iL of the chutes 50,these extensions forming the holders for the nuts while being tapped andbeing notched (see Fig. 5) to permit the free movement of theejector-plates `75, .as described'. Said plates are formed with orifices75L in their inner portions, through which thenuts may Assuming that theparts are in the position shown lat the Vleft-hand end of Fig. 4 and inFig. 7 and that the shaft 56, with its attachments, is moving leftward,the bottommost nut has been tapped and lies on theim.- perforate outerportion of the ejector-plate 75. `Asthe parts 67 and 75 continueztheirmovement the former engages the lowermost blank, vwhile the completednut previously resting on the ejector-plate dropskinto the opening 7 5f,the parts then assuming theposition indicated at the right-hand end ofFig.l 4. When the tap 67 finishes its operation and lis withdrawn, theejector.- plate moves back correspondingly and the previously-finishednut is moved out of line with thechute dropsthrough the orifice 75,leaves the just-finished vnut blanks falls upon the outer or imperforateportion of the ejector-plate. (Seethe left-4 hand end of Fig. 4.) e Inconnection with thev ejection of the iin. ished product reference shouldbe had to Figs. 7and 8.. Fig. 7 shows the last-finished nut and thesuperimposed column of` blanks resting on the ejector-plate 75 and thetap in position to engage the lowermost blank. In this connection itshould be observed that the center of the tap is somewhat above thecenand as thev tap ter of the lowermost blank, so tha-t when said blankis engaged by the tap the entire column of blanks is slightly raised,asshown in Fig. 8. This leaves the last-finished nut free of all weightexceptingits own, and therefore there kis nothing to prevent its easymovement out of the `lower portion of the holder 50a. The machine beingcapable' of operating both with square and hexagonal nuts, toaccommodate these the ejector-plate is formed with a V-shaped groove75bin its outer or'imf perforate portion. Vil-hen a square nut is beingoperated upon, said nut lies with one side flat on the Aejector plateand bridges said groove 75h. This is indicated in Figs. 7 and and holder50 and v50", whereupon said nut"v the. column of; n

IOO

8. When, however, a hexagonal nut is operated on` the lowermost angle ofthe nut will enter the groove 75h, thus allowing the-nut and the blankabove it to v assume then the proper position with respect to the tap. IThis is indicated in Fig.-10. y

The finished nuts, falling through orifices in the table of the`machine, enter inwardly-in- -the nuts themselves are guided inward intoa tray 7 9, located in the middle of the machine. Below the tray 7 9 islocated an oil-reservoir 80, and from this reservoir a pipe 81 passesupward to a suitable pump 82, driven from a shaft and pulley locatedoutside of the frame. A pipe 84 passes upward from the pump 82 and hastwo branches 85, passing, respectively, to the oil-fonts 86, which arelocated ljust inward of the blank-hoppers 49. From said fonts 86drip-pipes 87 pass, these pipes being four in number, two for each font,and discharging directly over the respective taps, so as to supply thesame with the oil necessary for vthe tapping operation. The tray 7 9 isformed with a perforate bottom, (see Fig. 6,) so that the oilaccumulated on the nuts after the tapping operation may drain into thereservoir 80.

The general operation of the machine may be traced as follows: rlhehoppers 49 and the chutes 50 being filled with blanks, upon theoperation of the pulley 21 the shaft 18 will be driven, and by thebelt-shifting mechanism the movement of said shaft will be periodicallyreversed, thus reversing the gears 53 and causing the lever 34 to begiven a regular rocking movement. The operation of the lever 34 resultsin the alternate rising and falling of the slides 47, and thus thechutes 50 are kept filled with blanks. The rotation of the gears 53drives the shafts 5'6 simultaneously towardand from the ends of themachine, and by the operation before described the taps at one end ofthe machine are worked through the blanks, while at the other end of themachine they are being withdrawn. As the movement of the shafts 56 isreversed this order of operation also is reversed. Consequently theblanks being supplied with the necessary rapidity and being alwayspresent- .ed to and removed from the path of the taps there is nooperation of the machine intermediate the actual operation of the taps,these Vtaps being driven through and withdrawn from the nuts withoutinterruption, and owing to this fact the capacity of the machine islimited only by the speed at which it may be .possible to operate thetliread-cutting taps.

The modification shown in Figs. 11, 12, and 13 is a means whereby bothof the shafts 56 and their four taps may be driven by a singlelead-screw and whereby this screw may be placed and displaced at will,thus adapting the machine to many different screw pitches. The shafts 56are engaged by the gears 53 to be rotated therefrom and to slide freelytherein. The stub-shaft 53 turns with the gear 52 and drives two spurs88 and 89, to the latter of which is fastened the shaft 90, supportingit.

The opposite end of the screw is supported by a center or its equivalent92. 94 indicates the nut, which is removably held in a yoke 93, thisyoke being engaged with and carried by the shafts 56, so as to slide theshafts,vbut allow the free rotation thereof. The operation of thisdevice will be apparent and it will also be seen that by removing theelements 91 and 94 others of different or any desired pitch may beplaced in their stead.

Various changes in the form, proportions, and minor details of ourinvention may beresorted to at will without departing from the spiritand scope thereof. Hence we consider ourselves entitled to all suchvariations as may lie within the intent of our claims.

Having thus described our invention, we claim as new and desire tosecure by Letters Patent- 1. In atapping-machine, the combination of arevoluble and reciprocal shaft, a lead-screw and nut coacting therewithfor the purpose specified, a gear mounted. to turn loosely around theaxis of the shaft, means for reversely rotating the gear, a sleeve.slidably mounted on one end of the shaft, a slidable connection betweenthe sleeve and gear, means for yieldingly holding the sleeve againstsaid sliding movement, and a tool carried by the sleeve.

2. Inatapping-machine, the combination of a revoluble and reciprocalshaft, a lead-screw and nut coacting therewith for the purposespecified, a gear mounted to turn loosely around the axis of the shaft,means for reversely rotating the gear, a sleeve slidably mounted on oneend of the shaft, a slidable connection between the sleeve and gear,means for yieldingly holding the sleeve against said sliding movement, atool cariied by the sleeve, a second sleeve slidably mounted on theother end of the shaft, means for yieldingly holding the second-namedsleeve against said sliding movement, and a tool carried by thesecond-named sleeve.

3. In a tapping-machine, the combination of a revoluble and reciprocalshaft, a lead-screw and nut coacting therewitlnvfor the purposespecified, a reversibly-driven rotating' gear mounted axially coincidentto said shaft, a sleeve mounted to slide on and to turn with the shaft,means for yieldingly holding` the sleeve against said sliding movement,a tool carried by the sleeve, a member connected with and projectinglaterally from the sleeve, and a stud carried by the said gear andsliding in the said projected member.

4. ln a tapping-machine, the combination of a ievoluble and reciprocalshaft, a lead-screw and nut coacting therewith for the purposespecified, a i'eversely-driven rotary gear axially coincident to theshaft, a sleeve mounted on the shaft, a pin carried transversely by thelSuitable devices on this gear 89 removably shaft, said sleeve having` alongitudinal slot engage the lead-screw 91 to turn said screw. lreceiving the pin and allowing the sleeve lonlOO gitudinal movement onthe shaft,a disk attached to the sleeve, studs carried by the gear andfitted loosely in the disk, means for yieldand nut coacting therewithfor the purpose specified, a reversely-driven rotary gear axiallycoincident to the shaft, a sleeve mounted on the shaft, a pin carriedtransversely by the shaft, said sleeve having a longitudinal slotreceiving the ypin and allowing the sleeve longitudinal movement on theshaft, a disk attached to the sleeve, studs carried by the gear andfitted loosely in the disk, means for yieldingly holding the sleeveagainst said independent sliding movement, and a tool connected with thesleeve, said means for yieldingly holding the sleeve against its-slidingmovement comprising a spring-sustained pin carried in the sleeve andengaging a cavity in the shaft.

v6. In a tapping-machine, the combination of a revoluble and reciprocalshaft, a lead-screw and nut coacting therewith for the purposespecified, means forimparting a rotary movement to the shaft independentof the reciprocal movement thereof, a sleeve mounted on each end of theshaft, each sleeve having a longitudinal slot therein, a transverse pincarried by each end portion of the shaft and respectively fitted in theslots of the sleeves, and a yieldingly-sustained pin carried by eachsleeve, said pins fitting in cavities in the shaft to yieldingly holdthe sleeves against sliding on the shaft.

7. In a nut-tapping machine, the combination with the framing and avertically-extending feed-chu te, of means for mounting and operatingthe tap, said means comprising a reciprocal and revoluble shaft, a slidemounted on the framing of the machine and having' sliding connection`with the shaft, a spring yieldingly holding the slide to move with theshaft, said slide engaging a part of the framing as the tap moves intoinactive position and said spring being compressed during itsengagement, and an ejector attached to the slide and coacting with thetap, substantially as described.

8. The combination ofl a revoluble and re- 4 ciprocal tool carryingmember, `means for feeding the same, a reversely-driven gear axiallycoincident to said member, a sleeve mounted on the member, a pin carriedtransversely by the member, the sleeve having a longitudinal slotreceiving the pin and allowing the sleeve longitudinal movement on theshaft, a disk attached to the sleeve, a stud carried by the gear andfitted loosely in the disk, and means for yieldingly holding the sleeveagainst said independent sliding movement.

9. The combination of a revoluble and'reciprocal tool-carrying member,means for feeding the same, a reversely-driven gear axially coincidentto said member, a sleeve mounted on the member, a pin carriedtransversely bythe member, the sleeve havinga longitudinal slotreceiving the pin and allowing the sleevelongitudinal movement on theshaft, a disk attached to the sleeve, a stud carried by the gear andfitted loosely in the disk, and means for yieldingly holding the sleeveagainstsaid independent sliding movement, said means for yieldinglyholding the sleeve against its sliding movement comprising aspring-sustained pin carried. by the sleeve and engaging' a cavity inthe said tool-carrying member.

10. In a nut-tapping machine, the combination with the framing and thework-holding means, of means for mounting-and operating the tap, saidmeans comprising a reciprocal and revoluble member, a slide mounted onthe framing and having sliding connection with said reciprocal andrevoluble member, a spring coacting with the slide and said memberyieldingly to connect the two, and an ejector, attached to the slide andcoacting with the tap and work-holding means.

11. In a tapping-machine, the combination with the frame, of arevolubleand reciprocal shaft, a reversely-driven gear mounted to turn freelyaround the axis of the shaft, a sleeve mounted to slide but not to turnon the shaft, a pin carried by said gear, means establishing slidingconnection between the pink and sleeve, a tap carried bythe sleeve,means for yieldingly restraining the slidingmovement of the sleeve, andmeans for feeding the shaft simultaneously with the rotary movementthereof. I

l2. In a tapping-machine, the combination oftwo revoluble and reciprocaltool-carrying members, means for rotating the same, a yoke extendingbetween and connected with said members to impart reciprocal movementthereto, a nut carried by the yoke, a screw engaged with the nut, andmeans for rotating the screw.

13. In a tapping-machine, the combination y'withthe frame, of tworevoluble and reciprocal tool-carrying members, means for rotating thesame, aA yoke extending between and connected with vsaid members toreciprocate them, anut, a screw engaged therewith, one of the twolast-named elements being carried by the yoke, and the other sustainedindependently thereof, and means for rotating said other one of saidelements.

14. In a tapping-machine, the combination. with a frame, of tworevoluble and reciprocal tool-carrying members, means for rotating thesame, a yoke extending transversely between said members and looselyconnected therewith to impart reciprocal movement thereto, and meansacting on the yoke intermediate its IOO IIO

ends for bodily moving the same, 'whereby to impart said reciprocalmovement.

15..In a tapping-machine, the combination ISO lthe dri ve-shaft.

of a revoluble and reciprocal tool-carrying member, means for revolvingthe same, a part y loosely engaged with said member to reciprocate it, anut removably carried by said part, a screw, means forrevolubly-mounting the screw, and means for revolnbly driving it, thesaid means for mounting the screw comprising releasable parts whereby topermit the removal and substitution of the screw.

16. In a tapping-machine, the combination of two revoluble andreciprocal tool-carrying members, a yoke loosely engaged therewith andextending between the same, a nut carried by the yoke, anindependemily-mounted screw coacting with the nut, a gearY in connectionwith the screw, a drive-shaft, a gear thereon and meshed with the gearconnected with the screw, a second gear on the drive-shaft, and a gearsplined on each of said tool-carrying members and meshed with the secondgear on 17. The combination of two revoluble and reeiproeally-mountedtool-carrying members, ayoke extending between the same and loosely lengaged therewith, a nut carried by the yoke, a screw engaged with. thenut, a revoluble shaft, a gear carried thereby, means for connecting'one end of the screw and the gear to turn the screw from the gear, acenter engaging the opposite end of the screw, a driven shaft, a gearthereon meshed with the lirstnamed gear, a second gear on the drivenshaft, and gears splined on the tool-carrying members and respectivelymeshcd with the second gear on the driven shaft.

18. In a tapping-machine, the combination with the frame of a revolubleand reciprocal shaft, a revcrsely-driven gear mounted to turn freelyaround the axis of the shaft, a tool-carrying member arranged to slideon the shaft and to turn therewith, means establishing' a slidingconnection between said member and the reversely-driven gear,meansforyiel dingl y restraining the independent sliding movement of the saidmember, and means for feeding` the shaft simultaneously with the rotarymovement thereof.

In testimony whereof we have .signed our names to this specilica'tion inthe presence of two subscribing witnesses.

GEORGE .E ZVVILLING. CHARLES RICHARDS.

fitnessem KATHERINE L. Sn'rrn, A. J. Mmmm.

